A new mandarin citrus tree of the mandarin tree Citrus reticulata is described. The new variety named xe2x80x98Moriaxe2x80x99 is desirable to the consumer because of the flavor of the juice and low seed number (0-6 seeds per fruit) and late ripening time (January to mid-April).
The present invention relates to a new distinct variety of mandarin tree Citrus reticulata developed by inventors Aliza Vardi, Pinchas Spiegel-Roy, Avraham Elchanati, Ahuva Frydman-Shani, and Hana Neumann in Bet Dagan, Israel from a selection of plants grown from irradiated bud wood of the cultivar xe2x80x98Murcottxe2x80x99.
Asexual reproduction by conventional bud grafting of the new variety in Israel by grafting has shown that the new characteristics are stabilized and permanently fixed through successive propagations.
The objective in breeding the present new tree variety, known by the cultivar name xe2x80x98Moriaxe2x80x99, was to obtain a late ripening mandarin citrus tree bearing fruit with few or no seeds. In the spring of 1986 and 1987 about 400 buds of an easy peeling mandarin cultivar, xe2x80x98Murcottxe2x80x99, were irradiated at the Nahal Soreq Nuclear Center, Yavne, Israel, by exposure to 3.5-4.0 kh of gamma radiation from a Co60 source. Sour orange nucellar rootstocks were bud grafted with the individual buds of irradiated xe2x80x98Murcottxe2x80x99 bud wood and labeled mV1. Six to nine months after grafting the irradiated budwood, individual buds from the mV1 plants were re-grafted on Sour orange nucellar rootstocks to establish about 700 mV2 plants.
Field planting was established from container grown mV2 plants in the spring of 1988 and 1989. The first fruits were observed in January-March 1990 and again in 1991 and 1992.
One of the selections, designated 3/38/55, had medium to large size orange color fruit and was easy to peel. This selection was distinguished from xe2x80x98Murcottxe2x80x99 as having fruit with 0-6 seeds compared with 15-30 seeds for xe2x80x98Murcottxe2x80x99. The selection typically had 0-6 seeds per fruit.
3/38/55 has flowers with low pollen fertility with 6% of the pollen grains typically stained with acetocarmine compared with 92% for xe2x80x98Murcottxe2x80x99.
The new tree, designated xe2x80x98Moriaxe2x80x99 was characterized by fruit with very few seeds and flowers having anthers bearing pollen with low fertility. Table 1 compares some of the characteristics of the new cultivar, named xe2x80x98Moriaxe2x80x99, and the parent xe2x80x98Murcottxe2x80x99.
The following is a detailed description of the new mandarin citrus based on observations made under typical Israeli grove conditions.
The tree shape and fruit appearance are similar to that of xe2x80x98Murcottxe2x80x99. The tree is vigorous. Small thorns, 1 mm to 3 mm are usually present in the leafy part of branches, especially in the lower portion and on the lower part of fruit bearing branches. Main branches have an upright attitude and young shoots have no anthocyanin coloration at the tip.
The bearing of the tree is regular and the productivity is relatively high, about the same as for xe2x80x98Murcottxe2x80x99. The canopy is moderately dense and there is little tendency to form water sprouts from scions. After pruning, the newly formed branches grow upright. The bark of the young shoots is initially smooth and green gradually turning into a smooth yellow-green. The chromosome number from the morphological characteristics of the tree is assumed to be the same as the parent 2n=18.
The leaves are similar to that of xe2x80x98Murcottxe2x80x99. They are small to medium in size, lanceolate, and sharp pointed. Leaf blades are firm, without undulation and slightly concave in cross section. Petioles are without wings or have rudimentary wings.
The characteristics of the flowering and the flower part are similar to those of xe2x80x98Murcottxe2x80x99. Flowering for both occurs at the end of March or the first half of April as measured in Bet Dagan, Israel. Both xe2x80x98Moriaxe2x80x99 and xe2x80x98Murcottxe2x80x99 produce about the same number of flowers and flower drop for both occurs in April. Terminal flower buds have no anthocyanin coloration. Flowers are borne singly and have an average number of stamens (about 20) with complete style development. Anther color is pale yellow. Pollen fertility is low as indicated by the observation that only 6% of the pollen grains were stained with acetocarmine in a test conducted at The Agricultural Research Organization, the Volcani Center, as compare with stainability of about 92% for Murcott pollen grain.
The fruit has few seeds, about 0 to 6 seeds, even when optimal pollination conditions are employed. This compares with about 27 seeds per fruit in xe2x80x98Murcottxe2x80x99. In other respects the fruit characteristics are in the range of the parent cv. xe2x80x98Murcottxe2x80x99. The fruit shape is oblate and it is medium sized. When 50 fruit were measured, the fruit had an average weight 115 grams, and average height 52 mm, and an average diameter 110 mm. The fruit has a moderately depressed stalk end. The fruit surface is usually smooth with a yellow orange color, 23B on The Royal Horticultural Society of London Colour Chart, and bears an average number of conspicuous rind oil glands. Fruit color and ripening do not differ from outside of the canopy to the inside, but the fruit color of the outside canopy are a little brighter as compare to the fruit color of the inside canopy. There is no persistence of the style and the areola is not completely developed. A navel is absent or very rare. The rind is thin and easy to peel.
The color of the albedo is white and the flesh is orange in color. The fruit contains 9-11 segments and is very juicy. The external color of the seeds is white when fresh. The internal seed coat is greyed orange and the cotyledons are green white. Polyembryony is similar to that of the parent xe2x80x98Murcottxe2x80x99. The seed sizes, shape and texture are similar to that of the parent xe2x80x98Murcottxe2x80x99. The fruit reaches maturity late in the season as does xe2x80x98Murcottxe2x80x99, which in Israel was February to April. The ripening of the fruit on the tree and within the fruit is uniform. Fruit remaining on the tree does not regreen and does not begin to lose quality until end of April. If there is a heavy crop and the fruits are not picked before March it may becomes alternate bearing (light crop the following season). Pre-harvest drop of both developed and undeveloped fruit is similar to that of the parent cv xe2x80x98Murcottxe2x80x99. The juice has an excellent test and flavor.